Electrophotographic copying machine

ABSTRACT

An electrophotographic copying machine of the type using a drum type photosensitive medium provided with a cleaning system. The cleaning system includes a blade of resilient material oriented in a counterdirection relative to the direction of movement of the photosensitive medium and having one edge disposed in contact with the medium, a cleaning tank, and circuitry for applying cleaning liquid to the areas of the medium and the blade near the contact area therebetween before the process is started.

United States Patent Saito et al.

111 E Re. 28,568

[ Reissued Oct. 14, 1975 ELECTROPHOTOGRAPHIC COPYING MACHINE Inventors:Takashi Saito, Tokyo; Yujiro Ando,

Yokohama, both of Japan Canon Kabushiki Kaisha, Tokyo, Japan Apr. 19,1974 Assignee:

Filed:

Appl. No.: 462,327

Related U.S. Patent Documents Reissue of:

' Mar. 30, 1970 Japan....

Patent No.: Issued: Appl. No.: Filed:

3,711,796 Jan. 16, 1973 166,820

July 28, 1971 Foreign Application Priority Data July 29, 1970 Japan45-66295 45-26736 [56] References Cited UNITED STATES PATENTS 2,634,2214/1953 McAlpine et al. 15/256.51 X 2,878,120 3/1959 Mayer et al 355/17 X2,889,758 6/1959 Bolton 1l8/DIG. 23 X 3,011,474 12/1961 Ulrich 355/15 X3,186,838 6/1965 Graff et a1. 15/1.S X 3,372,027 3/1968 Gundlach et a1.355/10 X 3,500,793 3/1970 Banusek 354/319 X 3,552,850 1/1971 Royka eta1... 355/15 3,654,654 4/1972 Abreu et al... l5/l.5 3,660,863 5 /1972Gerbasi 15/256.51

Primary ExamirierFred L. Braun Attorney, Agent, or FirmFitzpatrick,Cella, Harper & Scinto [5 7] ABSTRACT An electrophotographic copyingmachine of the type using a drum type photosensitive medium providedwith a cleaning system. The cleaning system includes a blade ofresilient material oriented in a counterdirection relative to thedirection of movement of the photosensitive medium and having one edgedisposed in contact with the medium, a cleaning tank, and circuitry forapplying cleaning liquid to the areas of the medium and the blade nearthe contact area therebetween before the process is started.

29 Claims, 6 Drawing Figures Reissued 0m. 14, 1975 Sheet 1 of3 Re.28,568

FIG. I

Reissued Oct. 14, 1975 Sheet 2 Of3 Re. 28,568

MAIN SWITCH 25 "ON" I 2 PUMP"ON" O E I I I IO 27m ROTARYHSRITENOIDSUPP'LAED To V 2 DRUM ROTATED DEVELOPING ROTARY SOLENOID LIQUID 30'\"OFF" SUPPLIEQTO BATH 2 H6. 3 FIG. 3(b) r 8(DISTRIBUTOR) FIG. 31C)ROTARY SOLENOID 1 Reissued Oct. 14, 1975 Sheet 3 of3 Re. 28,568

FIG. 4

FIG. 5

ELECTROPI-IOTOGRAPHIC COPYING MACHINE Matter enclosed in heavy bracketsI: appears in the original patent but forms no part of this reissuespecification; matter printed in italics indicates the additions made byreissue.

BACKGROUND OF THE INVENTION In the electrophotographic copying machinesof the described type, the residual developing liquid remaining on thesurface of the photosensitive medium after image transfer may besolidified due to the I: deffeciency J deficiency of the carrier liquidtherein. The developing liquid also tends to remain unremoved in thecontact area between the photosensitive medium and the blade andsolidify clue to the evaporation of the carrier liquid while the machineis out of operation. Such solidified developing liquid, i.e. solidifiedtoner, would build up between the photosensitive medium and the bladeand impart damages to the surface of the photosensitive medium or theblade when the machine resumes operation. This is more likely to occurat the beginning of every day service.

SUMMARY OF THE INVENTION The foregoing problems existing in the priorart may be solved by the present invention, which enables eithercleaning liquid serving as carrier or developer or liquid for exclusiveuse as cleaning liquid to be applied to the photosensitive medium and tothe blade, thereby bringing any solidified toner thereon into wetcondition and thus cleaning up the photosensitive medium by means of theblade.

The present invention is applicable to an electrophotographic copyingmachine in which the surface of a drum type photosensitive medium issubjected to a series of usual electrophotographic processes such aselectrostatic latent image formation, development, transfer, cleaning.The present invention is particularly concerned with the cleaningprocess succeeding to the transfer process, i.e. removal of any residualdeveloping liquid left on the surface of the photosensitive medium bythe use of a blade. During the cleaning process, the cleaning liquid isejected to the areas of the blade and photosensitive medium near thecontact area therebetween and the cleaning or developing liquidimpinging on the blade is flowed for collection along the grooves formedat the opposite end portions of the photosensitive drum. Such ejectionof the liquid is most effective when the machine is used after atemporary cessation of operation or at the beginning of its dailyservice. The drum type photosensitive medium remains stationary withoutrotation until the solidified toner or the like on and near the blade iswetted.

Embodiments of the present invention will be described hereunder inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS:

FIG. 1 is a schematic illustration of an embodiment of theelectrophotographic copying machine of the type in which cleaning liquidis ejected down to a drum type photosensitive medium and to a bladeadjacent thereto.

FIG 1a is a schematic cross-section of the drum type photosensitivemedium shown in FIG -1.

FIG. 2 is a block diagram showing the control of liquid supply to liquidtype developing means and to cleaning means.

FIG. 3 a is an enlarged perspective view of a distributor used in theelectrophotographic copying machine of FIG. 1;

FIG. 3 b is a schematic medial, sectional view showing the distributorof FIG. 3(a) in its position for distributing liquid solution to thecleaning liquid application means;

FIG. 3 c is a schematic medial, sectional view similar to FIG. 3(b), butshowing the distributor in its position for distributing liquid to boththe developing means and the cleaning liquid application means;

I: FIG. 4 is a perspective view of the cleaning means according toanother embodiment of the present invention.

FIG. 5 is a top plan view of the cleaning means shown in FIG. 4.]

DESCRIPTION OF THE PREFERRED EMBODIIVIENTS Referring to FIG. 1, there isshown a drum type electrophotographic copying machine, and moreparticularly, an arrangement for supplying cleaning liquid to a cleaningportion. The machine includes various means arranged around a drum typephotosensitive medium l rotatable in the direction of arrow, such asprimary charger 13, AC corona discharger 14, light image exposure means15, whole surface exposure means 17, liquid type developing means 2,post charger l8, transfer means 21, cleaning means which will bedescribed. In FIG. 1, the liquid type developing means 2 and the bladetype cleaning means are shown particularly in detail. Cleaning liquidsupply means is so constructed that developing liquid 5 in a tank 4 forthe developing means 2 may be utilized as cleaning liquid. The machineis such that when the main switch thereof (not shown) is closed, a drivesource 7 for liquid delivery means 6 such as a centrifugal pump or thelike is energized to supply the developing liquid 5 from the tank 4through distributor means 8 into a pipe 9 terminating at a spray conduit10, through which the developing liquid is applied to a blade 3 and tothe surface of the photosensitive medium 1. The liquid thus applied isflowed along the blade 3 toward the opposite ends thereof and collectedthrough grooves [not] shown in FIG. 1a provided at the opposite endportions of the photosensitive medium 1. During that while, thephotosensitive medium 1 remains stationary so that any solidified tonerpresent on the blade 3 and on the surface portion of the photosensitivemedium 1 adjacent to the blade is brought into wet condition.

Subsequently, a copy switch (not shown) is closed to rotate thephotosensitive medium 1 for a copying process and concurrentlytherewith, the distributor means 8 is changed over to supply thedeveloping liquid from the liquid delivery means 6 such a pump into thedeveloping bath or trough 2' of the developing means 2 and cut off theliquid supply to the spray Conduit 10.

Such arrangement ensures cleaning liquid to be supplied to the blade andthe surface of the photosensitive medium so asto wet the solidifiedtoner thereon before copying operation or rotation of the drum 1 isinitiated, thus obviating the possibility of inadvertently neglect ingsupply of the cleaning liquid.

instead of using the distributor means 8 such as a change-over valve orthe like, it is possible to employ such a design that liquid is suppliedboth to the cleaning portion and the developing bath 2 all the time whenthe main switch is closed.

The block diagram of FIG. 2 shows the control of the liquid supply. Uponclosing of the main switch 25, the pump 26 is operated while the rotarysolenoid 27 is rotated, so that the cleaning liquid is supplied to theliquid application means l0.'When the print button 28 is closed, thephotosensitive medium starts rotating while the rotary solenoid 27 isstopped from rotating. As a result, developing liquid is supplied intothe developing bath 2'.

FIG. 3 shows details of the distributor means 8. FIG. 3 b shows thedistributor means in the position for distributing the liquid solely tothe cleaning liquid application means 10, and FIG. 3 c shows theposition for distributing the liquid both to the developing means 2 andthe cleaning liquid application means 10.

[FIGS 4 and show another embodiment of the cleaning means. As shown, ablade 39 supported by supporting plates 40 and 42 is disposed with oneside edge thereof in contact with the photosensitive medium 1. Thephotosensitive medium has a pair of grooves 1 formed circumferentiallyat the opposite end portions thereof. The blade 39 has a liquid blockingplate 41 provided at one end thereof in such a manner that the side edge41a of the liquid blocking plate 41 is received in the groove 1 formedat one end 38 of the photosenstiive medium 1. Above the other end of theblade 39 which is remote from the liquid blocking 41, there is disposeda developing liquid application conduit 43 with its open end portionsomewhat inclined downwardly. When developing liquid is dischargedthrough the developing liquid application conduit 43, the liquiddischarged is allowed to stay in the contact area be tween the surfaceof the photosensitive medium and the blade 39 due to the flow rate ofthe liquid and to the liquid blocking plate 41. Thus, the toner stickingto such area can readily be wetted and fluidized by the liquid.

If desired, the blade 39 may be inclined downwardly with respect to thedeveloping liquid application conduit 43 so as to enhance the stayingeffect of the developing liquid with the aid of the flow rate and theliquid blocking plate. 1

We claim:

1. An electrophotographic copying machine including a photosensitivemedium, electrostatic latent image Formation means, liquid typedeveloping means, trans- Fer means and cleaning means,'saidphotosensitive medium having developing liquid collection grooves formedat the opposite end portions thereof, said cleaning means comprising ablade of resilient material having one edge disposed in contact withsaid medium, a cleaning liquid tank, and means for applying cleaningliquid to the areas of said medium and said blade near the contact areatherebetween before cleaning action is started.

2. An electrophotographic copying machine as defined in claim 1, whereinsaid cleaning means further comprises liquid delivery means fordelivering cleaning liquid from said cleaning liquid tank to saidcleaning liquid application means.

3. An electrophotographic copying machine as defined in claim 2, whereinliquid in said cleaning liquid tank is developing liquid, and saidliquid delivery means delivers developing liquid from said tank to saidcleaning liquid application means and to said liquid type developingmeans.

4. An electrophotographic copying machine as defined in claim 3, whereinsaid liquid delivery means includes distributor means for distributingthe developing liquid from said cleaning liquid tank to said cleaningliquid application means before cleaning action is started, and fordistributing the developing liquid from said tank to said developingmeans during the cleaning action.

[5. An electrophotographing copying machine as defined in claim 1,wherein said cleaning liquid application means includes a developingliquid conduit disposed adjacent to one end of said blade in such amanner that the open end portion of said conduit is somewhat inclineddownwardly, and a cleaning liquid blocking plate provided at the otherend of said blade in corresponding relationship with one of said groovesformed on said photosensitive medium. :I

6. An electrophotographic copying machine as defined in claim 1, whereinsaid blade is oriented in a counter-direction with respect to thedirection of movement of said photosensitive medium.

7. An electrophotographic copying machine including a medium capable ofbearing thereon an electrostatic latent image of the original to becopied, means for establishing said electrostatic latent image on saidmedium, liquid developing means for developing said electrostatic latentimage, transfer means for transferring the thus developed image to copymaterial and cleaning means, said cleaning means comprising a cleaningmember disposed in contact with said medium for cleaning same forrepeated use, a cleaning liquid tank, and means for applying cleaningliquid from said liquid tank to the areas of both said medium and saidcleaning member near the contact area therebetween before cleaningaction of said cleaning member is started.

8. An electrophotographic copying machine asdefined in claim 7, whereinsaid cleaning means further comprises liquid delivery means fordelivering cleaning liquid from said cleaning liquid tank to said meansfor applying cleaning liquid.

9. An electrophotographic copying machine as defined in claim 8, whereinliquid in said cleaning liquid tank is developing liquid, and saidliquid delivery means delivers developing liquid from said tank to saidmeans for applying cleaning liquid and to said liquid developing means.

10. An electrophotographic copying machine as defined in claim 9,wherein said liquid delivery means includes distributor means fordistributing the developing liquid from said cleaning liquid tank tosaid means for applying cleaning liquid before cleaning action isstarted, and for distributing the developing liquid from said tank tosaid liquid developing means during the dahin de- 11. Anelectrophotographiccopying de fined in claim 7 further comprising meansfor collecting cleaning liquid applied to said mediurn'and said cleaningmember.

12. An electrophotographiccopying machine including a medium capable ofbearing thereon an electrostaticjlatent imageof the original to becopied, means for establishing said electrostatic latent image on saidmedium, liquid developing means for developing said electrostaticlatentimage, transfer means for transferring the thus developed image tocopy material and cleaning means, said cleaning means comprising a bladeof resilient material having one edge disposed incontact with saidmedium for cleaning same for repeated use, a cleaning liquid tank, andmeans for applying cleaning liquid from said liquid tank to the areas ofboth said medium and said blade near the contact area therebetweenbefore cleaning action of said cleaning blade is started.

13. An electrophotographic copying machine as defined in claim 12,wherein said cleaning means further comprises liquid delivery means fordelivering cleaning liquid from said cleaning liquid tank to said meansfor applying cleaning liquid.

14. An electrophotographic copying machine as defined in claim 13,wherein liquid in said cleaning liquid tank is developing liquid, andsaid liquid delivery means delivers developing liquid from said tank tosaid means" for applying cleaning liquid and to said liquid developingmeans.'

15. An electrophotographic copying machine as defined in claim 14,wherein said liquid delivery means includes distributor means fordistributing the developing liquid from said cleaning liquid tank tosaid means for applying cleaning liquid before cleaning action isstarted, and for distributing the developing liquid from said tank tosaid liquid developing means during the cleaning action.

I 6. An electrophotographic copying machine as defined in claim 12further comprising means for collecting cleaning liquid applied to saidmedium and said blade.

17. An electrophotographic copying machine as defined in claim 12,wherein said means for applying cleaning liquid includes a liquidconduit having an opening therein disposed adjacent to said blade withthe opening inclined downwardly.

18. An electrophotographic copying machine including a photosensitivemedium in the form of a rotary drum electrostatic latent image formationmeans for forming on said photosensitive medium an electrostatic imageof the original to be copied, liquid developing means for developingsaid electrostatic latent image, transfer means for transferring thethus developed image to copy mate rial, and cleaning means, saidcleaning means comprising a blade of resilient material having one edgedisposed in contact with said medium, a cleaning liquid tank, and meansfor applying cleaning liquid from said liquid tank to the areas of bothsaid medium and said blade near the contact area therebetween beforecleaning action of said blade is started.

19. An electrophotographic copying machine as defined in claim 18,wherein said cleaning means further comprises liquid delivery means fordelivering cleaning liquid from said cleaning liquid tank to said meansfor applying cleaning liquid.

20. An'electrophotographic' copying machine as defined in 51mm 19,wherein'liquid in said cleaning liquid tank is developing liquid, andsaid liquid delivery means delivers developing liquid from said tank tosaid means for applying cleaning liquid and 'to sdid liquid developingmean s." V 'l 21 An electrophotographic copying machine as defined inclaim 20, wherein liquid delivery means includes distributor fordistributing the developing liquid from said'cl'eaning liquid tarikio'sdid means for applying cleaning liquid before cleaning action isstarted, and for distributing the developing liquid from said tank tosaid liquid developing means during thecleaning ac- 22. Anelectrophotographictopyihghmachine as 'defined inclaim [furthercomprising means for collecting cleaning liquid applied to a medium andsaid blade.

23. An electrophotographic copying machine as defined inclaim 18,wherein said means for applying cleaning liquid includes a liquidconduit having an opening therein disposed adjacent to said blade withthe opening inclined downwardly.

24. An electrophotographic copying machine including a photosensitivemedium, electrostatic latent image formation means for forming on saidphotosensitive medium an electrostatic image of the original to becopied, liquid developing means, post charger means for applying acorona charge on the thus developed image, transfer means for thereaftertransferring the developed image to copy material, and cleaning means,said cleaning means comprising a blade of resilient material having oneedge disposed in contact with said medium, a cleaning liquid tank. andmeansfor applying cleaning liquid from said liquid tank to the areas ofboth said medium and said blade near the contact area therebetweenbefore cleaning action of said blade is started.

25. An electrophotographic copying machine including a drum type mediumrotatable about a horizontal axis and capable of bearing thereon anelectrostatic latent image of the original to be copied, means forestablishing said electrostatic latent image on said medium, liquiddeveloping means positioned below the horizontal axis. of said drum typemedium for developing said electrostatic latent image, transfer meansfor transferring the thus developed image to copy material and cleaningmeans, said cleaning means comprising a cleaning member disposed incontact with said medium for cleaning same for repeated use, a cleaningliquid tank, and means for applying cleaning liquid from said liquidtank to the areas of both said medium and said cleaning member near thecontact area therebetween before cleaning action of said cleaning memberis started, said transfer means, cleaning means and means forestablishing the latent image being positioned sequentially around thedrum type medium from the developing means in the direction of rotation.

26. An electrophotographic copying machine as in claim 25 wherein saidcleaning means is located above said horizontal axis and at theperiphery of said drum type medium where it rotates downwardly.

27. An electrophotographic copying machine including a drum type mediumrotatable about a horizontal axis and capable of bearing thereon anelectrostatic latent image of the original to be copied, means forestablishing said electrostatic latent image on said medium, liquiddeveloping means positioned below the horizontal axis of said drum typemedium for developing said electrostatic latent image, transfer meansfor transferring the thus dedium from the developing means in thedirection of rota- I tion.

28. An electrophotographic copying machine as in claim 27 wherein saidcleaning means is located above said horizontal axis and at theperiphery of said drum type medium where it rotates downwardly.

29. An electrophotographic copying machine including a drum typephotosensitive medium rotatable about a horizontal axis, electrostaticlatent image formation means for forming on said photosensitive mediuman electrostatic image of the original to be copied, liquid developingmeans positioned below the horizontal axis of said drum typephotosensitive medium for developing said electrostatic latent image,transfer means for transferring the thus developed image to copymaterial, and cleaning means, said cleaning means comprising a blade ofresilient material having one edge disposed in contact with said medium,a cleaning liquid tank, and means for applying cleaning liquid from saidliquid tank to the areas of both said medium and said blade near thecontact area therebetween before cleaning action of said blade isstarted, said transfer means, cleaning means and means for forming thelatent image being positioned sequentially around the drum typephotosensitive medium from the developing means in the direction ofrotation.

30. An electrophotographic copying machine as in claim 29 wherein saidcleaning means is located above said horizontal axis and at theperiphery of said drum type medium where it rotates downwardly.

1. An electrophotographic copying machine including a photosensitivemedium, electrostatic latent image formation means, liquid typedeveloping means, transfer means and cleaning means, said photosensitivemedium having developing liquid collection grooves formed at theopposite end portions thereof, said cleaning means comprising a blade ofresilient material having one edge disposed in contact with said medium,a cleaning liquid tank, and means for applying cleaning liquid to theareas of said medium and said blade near the contact area therebetweenbefore cleaning action is started.
 2. An electrophotographic copyingmachine as defined in claim 1, wherein said cleaning means furthercomprises liquid delivery means for delivering cleaning liquid from saidcleaning liquid tank to said cleaning liquid application means.
 3. Anelectrophotographic copying machine as defined in claim 2, whereinliquid in said cleaning liquid tank is developing liquid, and saidliquid delivery means delivers developing liquid from said tank to saidcleaning liquid application means and to said liquid type developingmeans.
 4. An electrophotographic copying machine as defined in claim 3,wherein said liquid delivery Means includes distributor means fordistributing the developing liquid from said cleaning liquid tank tosaid cleaning liquid application means before cleaning action isstarted, and for distributing the developing liquid from said tank tosaid developing means during the cleaning action. (
 5. Anelectrophotographing copying machine as defined in claim 1, wherein saidcleaning liquid application means includes a developing liquid conduitdisposed adjacent to one end of said blade in such a manner that theopen end portion of said conduit is somewhat inclined downwardly, and acleaning liquid blocking plate provided at the other end of said bladein corresponding relationship with one of said grooves formed on saidphotosensitive medium.)
 6. An electrophotographic copying machine asdefined in claim 1, wherein said blade is oriented in acounter-direction with respect to the direction of movement of saidphotosensitive medium.
 7. An electrophotographic copying machineincluding a medium capable of bearing thereon an electrostatic latentimage of the original to be copied, means for establishing saidelectrostatic latent image on said medium, liquid developing means fordeveloping said electrostatic latent image, transfer means fortransferring the thus developed image to copy material and cleaningmeans, said cleaning means comprising a cleaning member disposed incontact with said medium for cleaning same for repeated use, a cleaningliquid tank, and means for applying cleaning liquid from said liquidtank to the areas of both said medium and said cleaning member near thecontact area therebetween before cleaning action of said cleaning memberis started.
 8. An electrophotographic copying machine as defined inclaim 7, wherein said cleaning means further comprises liquid deliverymeans for delivering cleaning liquid from said cleaning liquid tank tosaid means for applying cleaning liquid.
 9. An electrophotographiccopying machine as defined in claim 8, wherein liquid in said cleaningliquid tank is developing liquid, and said liquid delivery meansdelivers developing liquid from said tank to said means for applyingcleaning liquid and to said liquid developing means.
 10. Anelectrophotographic copying machine as defined in claim 9, wherein saidliquid delivery means includes distributor means for distributing thedeveloping liquid from said cleaning liquid tank to said means forapplying cleaning liquid before cleaning action is started, and fordistributing the developing liquid from said tank to said liquiddeveloping means during the cleaning action.
 11. An electrophotographiccopying machine as defined in claim 7 further comprising means forcollecting cleaning liquid applied to said medium and said cleaningmember.
 12. An electrophotographic copying machine including a mediumcapable of bearing thereon an electrostatic latent image of the originalto be copied, means for establishing said electrostatic latent image onsaid medium, liquid developing means for developing said electrostaticlatent image, transfer means for transferring the thus developed imageto copy material and cleaning means, said cleaning means comprising ablade of resilient material having one edge disposed in contact withsaid medium for cleaning same for repeated use, a cleaning liquid tank,and means for applying cleaning liquid from said liquid tank to theareas of both said medium and said blade near the contact areatherebetween before cleaning action of said cleaning blade is started.13. An electrophotographic copying machine as defined in claim 12,wherein said cleaning means further comprises liquid delivery means fordelivering cleaning liquid from said cleaning liquid tank to said meansfor applying cleaning liquid.
 14. An electrophotographic copying machineas defined in claim 13, wherein liquid in said cleaning liquid tank isdeveloPing liquid, and said liquid delivery means delivers developingliquid from said tank to said means for applying cleaning liquid and tosaid liquid developing means.
 15. An electrophotographic copying machineas defined in claim 14, wherein said liquid delivery means includesdistributor means for distributing the developing liquid from saidcleaning liquid tank to said means for applying cleaning liquid beforecleaning action is started, and for distributing the developing liquidfrom said tank to said liquid developing means during the cleaningaction.
 16. An electrophotographic copying machine as defined in claim12 further comprising means for collecting cleaning liquid applied tosaid medium and said blade.
 17. An electrophotographic copying machineas defined in claim 12, wherein said means for applying cleaning liquidincludes a liquid conduit having an opening therein disposed adjacent tosaid blade with the opening inclined downwardly.
 18. Anelectrophotographic copying machine including a photosensitive medium inthe form of a rotary drum electrostatic latent image formation means forforming on said photosensitive medium an electrostatic image of theoriginal to be copied, liquid developing means for developing saidelectrostatic latent image, transfer means for transferring the thusdeveloped image to copy material, and cleaning means, said cleaningmeans comprising a blade of resilient material having one edge disposedin contact with said medium, a cleaning liquid tank, and means forapplying cleaning liquid from said liquid tank to the areas of both saidmedium and said blade near the contact area therebetween before cleaningaction of said blade is started.
 19. An electrophotographic copyingmachine as defined in claim 18, wherein said cleaning means furthercomprises liquid delivery means for delivering cleaning liquid from saidcleaning liquid tank to said means for applying cleaning liquid.
 20. Anelectrophotographic copying machine as defined in claim 19, whereinliquid in said cleaning liquid tank is developing liquid, and saidliquid delivery means delivers developing liquid from said tank to saidmeans for applying cleaning liquid and to said liquid developing means.21. An electrophotographic copying machine as defined in claim 20,wherein said liquid delivery means includes distributor means fordistributing the developing liquid from said cleaning liquid tank tosaid means for applying cleaning liquid before cleaning action isstarted, and for distributing the developing liquid from said tank tosaid liquid developing means during the cleaning action.
 22. Anelectrophotographic copying machine as defined in claim 18 furthercomprising means for collecting cleaning liquid applied to said mediumand said blade.
 23. An electrophotographic copying machine as defined inclaim 18, wherein said means for applying cleaning liquid includes aliquid conduit having an opening therein disposed adjacent to said bladewith the opening inclined downwardly.
 24. An electrophotographic copyingmachine including a photosensitive medium, electrostatic latent imageformation means for forming on said photosensitive medium anelectrostatic image of the original to be copied, liquid developingmeans, post charger means for applying a corona charge on the thusdeveloped image, transfer means for thereafter transferring thedeveloped image to copy material, and cleaning means, said cleaningmeans comprising a blade of resilient material having one edge disposedin contact with said medium, a cleaning liquid tank, and means forapplying cleaning liquid from said liquid tank to the areas of both saidmedium and said blade near the contact area therebetween before cleaningaction of said blade is started.
 25. An electrophotographic copyingmachine including a drum type medium rotatable about A horizontal axisand capable of bearing thereon an electrostatic latent image of theoriginal to be copied, means for establishing said electrostatic latentimage on said medium, liquid developing means positioned below thehorizontal axis of said drum type medium for developing saidelectrostatic latent image, transfer means for transferring the thusdeveloped image to copy material and cleaning means, said cleaning meanscomprising a cleaning member disposed in contact with said medium forcleaning same for repeated use, a cleaning liquid tank, and means forapplying cleaning liquid from said liquid tank to the areas of both saidmedium and said cleaning member near the contact area therebetweenbefore cleaning action of said cleaning member is started, said transfermeans, cleaning means and means for establishing the latent image beingpositioned sequentially around the drum type medium from the developingmeans in the direction of rotation.
 26. An electrophotographic copyingmachine as in claim 25 wherein said cleaning means is located above saidhorizontal axis and at the periphery of said drum type medium where itrotates downwardly.
 27. An electrophotographic copying machine includinga drum type medium rotatable about a horizontal axis and capable ofbearing thereon an electrostatic latent image of the original to becopied, means for establishing said electrostatic latent image on saidmedium, liquid developing means positioned below the horizontal axis ofsaid drum type medium for developing said electrostatic latent image,transfer means for transferring the thus developed image to copymaterial and cleaning means, said cleaning means comprising a blade ofresilient material having one edge disposed in contact with said mediumfor cleaning same for repeated use, a cleaning liquid tank, and meansfor applying cleaning liquid from said liquid tank to the areas of bothsaid medium and said blade near the contact area therebetween beforecleaning action of said cleaning blade is started, said transfer means,cleaning means and means for establishing the latent image beingpositioned sequentially around the drum type medium from the developingmeans in the direction of rotation.
 28. An electrophotographic copyingmachine as in claim 27 wherein said cleaning means is located above saidhorizontal axis and at the periphery of said drum type medium where itrotates downwardly.
 29. An electrophotographic copying machine includinga drum type photosensitive medium rotatable about a horizontal axis,electrostatic latent image formation means for forming on saidphotosensitive medium an electrostatic image of the original to becopied, liquid developing means positioned below the horizontal axis ofsaid drum type photosensitive medium for developing said electrostaticlatent image, transfer means for transferring the thus developed imageto copy material, and cleaning means, said cleaning means comprising ablade of resilient material having one edge disposed in contact withsaid medium, a cleaning liquid tank, and means for applying cleaningliquid from said liquid tank to the areas of both said medium and saidblade near the contact area therebetween before cleaning action of saidblade is started, said transfer means, cleaning means and means forforming the latent image being positioned sequentially around the drumtype photosensitive medium from the developing means in the direction ofrotation.
 30. An electrophotographic copying machine as in claim 29wherein said cleaning means is located above said horizontal axis and atthe periphery of said drum type medium where it rotates downwardly.